var/external/wavelet/DWTAPartition.c

   1 // Author: Aime' Fournier
   2 // E-mail: fournier@ucar.edu
   3
   4 #include "qf.h"         // for IFH(), pqf ...
   5
   6 void DWTAPartition(     // create indexes for dwtai()
   7    int *iv,             // in iv[0]: data length/out iv[1:lm]: v-space lengths
   8    int *iw,             // out iw[0:lm]: w-space lengths
   9    int *ia,             // out: ia[0] transform length; ia[1:lm] w starts
  10    int lm,              // maximum level
  11    const pqf *h,        //  low-pass filter
  12    const pqf *g) {      // high-pass filter
  13    int j,lg,lh;         // index; filter lengths
  14
  15    lh=h->omega-h->alpha+1;
  16    lg=g->omega-g->alpha+1;
  17    for( j=1; j<=lm; j++ ) {
  18       iv[j]=IFH(iv[j-1]+lh);
  19       iw[j]=IFH(iv[j-1]+lg);
  20    }
  21    iw[0]=0;             // no w space at level 0
  22    ia[lm]=iv[lm];       // start of largest-scale w
  23    for( j=lm; j>=1; j-- )
  24       ia[j-1]=ia[j]+iw[j];
  25 }